Passersby walk in front of video monitors announcing the Carlyle Group's listing on the NASDAQ market site in New York's Times Square after the opening bell for trading, May 3, 2012.Keith Bedford

NEW YORK (Reuters) - Carlyle Group LP (CG.O) is preparing an initial public offering or a sale of PQ Corp that could value the specialty chemical company at up to $3 billion, including debt, people familiar with the matter said on Friday.

The private equity firm, which bought PQ for $1.5 billion in 2007, plans to talk to investment banks next week to choose underwriters for the proposed offering, the people said.

Carlyle will also explore an outright sale of PQ to another firm, in what is known as a dual-track process, they added, asking not to be identified by name because the matter is not public.

Malvern, Pennsylvania-based PQ is estimated to have around $300 million in annual earnings before interest, tax, depreciation and amortization and could fetch up to 10 times that amount in a potential sale, some of the people said.

Carlyle declined to comment, while PQ Corp did not respond to requests for comment.

The company is a major producer of inorganic specialty chemicals for industrial and consumer markets, including sodium silicate, silicate derivatives, catalysts, reflective glass spheres and engineered glass materials.

After its 2007 acquisition of PQ, Carlyle combined the company with industry peer INEOS Silicas, a division of petrochemical giant INEOS, to create a global producer of specialty chemicals, catalysts and engineered glass products. As part of the transaction, Carlyle retained a 60 percent stake in the newly combined company and INEOS the rest.

In 2011, PQ separated its engineered glass products subsidiary, Potters Industries, in order to pay down debt under its credit facility.

The company is coming to market at a time when private equity investors as well as industry buyers have showed strong interest for specialty chemical assets, driving deal making in the sector.